Biodegradable chitosan microparticles were prepared by a water-in-oil emulsion solvent diffusion method without any surfactants. Aqueous chitosan solution and ethyl acetate were used as the water and oil phases, respectively. The chitosan microparticles; with spherical, deflated, and hollow shapes, could be fabricated from different chitosan concentrations. Chitosan microparticle matrices were sponge-like. The particle sizes increased with the chitosan concentration and molecular weight. Cross-linked chitosan microparticles obtained from post-glutaraldehyde treatment showed rougher surfaces and denser matrices. The particle shapes did not change after cross-linking. The degrees of cross-linking of chitosan microparticles were in order of hollowdeflatedspherical shapes.